[RETRACTED ARTICLE] Bovine Vaccinia in dairy cattle and suspicion of vesicular disease on milkers in Brazil

Abstract

Bovine vaccinia (BV) is a vesicular disease induced by the Vaccinia virus (VACV) that affects milk production and is an occupational zoonosis. This research had the following objectives: (i) detection of VACV by qPCR in cattle with clinical suspicion of vesicular disease; (ii) symptoms characterization in animals and milkers with clinical suspicion of the disease and virus detection in humans; and (iii) identification of risk factors for infections of VACV in herds from several Brazilian states. A total of 471 bovine epithelial samples from dairy farms, in 15 Brazilian states, were evaluated between 2007 and 2012. The samples were tested by quantitative PCR (qPCR) using SYBR Green® reagents, validated with a lower limit of detection of 100TCID50/50µL (1.7x100 viral particles), and 45.1% of VACV positive samples were detected. Using official forms for epidemiological investigation (FORM-IN), the risk factors for VACV infections in cattle were determined to be farms with a lack of technological facilities (P= 0.029) and the presence of rodents (P= 0.001). There was an effect of seasonality in cattle with a higher occurrence of BV during the dry season. A total of 420 epidemiological questionnaires were applied at public health care centers, where 100% of the milkers had vesicular lesions on their hands (98.1%) and on their arms (6.9%). The most frequent clinical symptoms in humans were: local swelling (74.2%), headache (20.7%), fever (10.4%) and inguinal lymphadenopathy (74.2%). Only 19.98% of milkers aged between 39 and 58 years were seroreactive to VACV and were immunized with the human anti-smallpox vaccine. There was an increase in the frequency of BV in older individuals due to their natural decrease in specific immunity. It has been shown that the implementation of zootechnical management techniques and health planning are important for the prevention of BV in animals and humans.

Twenty Years after Bovine Vaccinia in Brazil: Where We Are and Where Are We Going?

“…However, the impact of milk and dairy products as vehicles for VACV spreading is still poorly explored. In regions recognized by the production as artisanal cheese, the burden of VACV maybe even more significant since the artisanal cheeses are essentially made with crude milk (no thermal processes are applied) [ 89 , 90 , 91 ].…”

Poxviruses diagnosed in cattle from Distrito Federal, Brazil (2015–2018)

“…Thirty-two cases were submitted to quantitative conventional PCR in the Laboratory of Cattle Viruses (LCV) of the Biological Institute (BI), in São Paulo, Brazil, according to Silva et al (2018). In the other three cases, the virological diagnosis of parapoxvirus was performed by virus neutralization assay, also in LCV/BI.…”

Retrospective study of poxviruses diagnosed in cattle from Goiás State, Brazil (2010-2018)

“…BV was diagnosed in three mesoregions, but predominantly in Southern. Most cases was observed in dairy cattle (11/13) in the dry season (12/13), as detected by other (Leite et al 2005, Assis et al 2015, Silva et al 2018, Alonso et al 2020. The clinical course varied of 12 to 45 days and the lesions consisted mainly of vesicles, ulcers and crusts affecting the teat and udder of cows.…”

“…Seventeen cases were submitted to quantitative PCR in the "Laboratório de Viroses de Bovídeos" (LVB) of the "Instituto Biológico" (IB-SP), in São Paulo, Brazil, according to Silva et al (2018). Molecular diagnosis was performed by a multiplex PCR in eight cases/outbreaks, for simultaneous detection of BPSV, PCPV, VACV and Bovine alphaherpesvirus 2 (BoHV-2) in the "Setor de Virologia" of the "Universidade Federal de Santa Maria", Santa Maria, Brazil, according to Cargnelutti et al (2017).…”